Preneoplastic Lesions as Early Indicators of Neoplastic Development

Abstract

In human pathology, the terms “preneoplasia” and “precancer” have traditionally been used as synonyms indicating a pathological condition carrying increased risk for the development of malignant neoplasia (cancer). In addition to definite proliferative lesions such as nodular hyperplasia, papilloma, or carcinoma in situ, dysplastic lesions have been considered potential prestages of cancer and have, hence, been widely involved in the early diagnosis of neoplasia (Carter 1984, and this volume; Koss 1979, and this volume). However, investigations in several animal models and some studies in man revealed that characteristic changes in the biochemical and morphological phenotype of focal cell populations, which initially deviate only slightly from the normal differentiated state, precede the appearance of both benign and malignant neoplasms in a number of tissues by weeks and months or even years (Bannasch 1986; Sirica 1989). This holds especially true for epithelial tissues endowed with a low cell turnover under normal conditions, such as the hepatic parenchyma (Bannasch et al. 1989a; Symposium 1989), exocrine pancreatic parenchyma (Longnecker and Millar 1990; Woutersen et al. 1991), and renal tubular system (Bannasch and Zerban 1990; Dietrich and Swenberg 1991), but it also relates to some epithelial tissues with a high cell turnover like the colonic mucosa (Mayer et al. 1987; Barrow et al. 1990) and bronchial mucosa (Gusterson 1984) (Table 1). Based on these findings, preneoplasia may be defined as phenotypically altered cell populations which have no obvious neoplastic nature but indicate an increased risk for the development of benign or malignant neoplasia in the respective tissue (Bannasch 1986).